REPRODUCTIVE ORGANS OF PLANTS. 293 
The forms of anthers, as well as of the grains of pollen, vary with nearly 
every kind of plant. The yellow pollen of pine and spruce trees is not 
infrequently transported by the wind to a great distance, and when 
brought down by rain in considerable quantities, has been mistaken for 
sulphur. 
The Pistil, », in fig’s 60 and 61, or pistils, occupy the 
center of the perfect flower. They are exceedingly va- 
rious in form, but always have at their base the seed-ves- 
sels or ovaries, ov, in which are found the ovules (little 
eggs) or rudimentary seeds. The summit of the pistil is 
destitute of the epidermis which covers all other parts of 
the plant, and is termed the stigma, st. 
As has been remarked, the floral organs may be consid- 
ered to be modified leaves; or rather, all the appendages 
of the stem—the leaves and the parts of the flower to- 
gether—are different developments of one fundamental 
organ. 
The justness of this idea is sustained by the transforma- 
tions which are often observed. 
The-rose in its natural state has a corolla consisting of 
five petals, but has a multitude of stamens and pistils. In 
arich soil, or as the effect. of those agencies which are 
united in “cultivation,” nearly all the pistils and stamens 
lose their reproductive function and proper structure, and 
revert to petals; hence the flower becomes double. The 
tulip, poppy, and numerous garden-flowers, illustrate this 
interesting metamorphosis, and in these flowers we may 
often see at once the change in various stages intermediate 
between the perfect petal and the unaltered pistil. 
On the other hand, the reversion of all the floral organs 
into ordinary green leaves has been observed not infre- 
quently, in case of the rose, white clover, and other 
plants. 
While the complete flower consists of the four sets of 
organs above described, only the stamens and pistils are 
essential to the production of seed. The latter, accord- 
